This disclosure relates to a system and method for detecting screen-out using a fracturing valve for mitigation.
Over the years, hydraulic fracturing with multiple fractures has been a popular method in producing gas and oil from a horizontal wells. Hydraulic fracturing involves injecting a highly pressurized fracturing fluid through a wellbore, which causes rock layers to fracture. Once cracks are formed, proppants are introduced to the injected fluid to prevent fractures from closing. The proppants use particulates, such as grains of sands or ceramics, which are permeable enough to allow formation fluid to flow to the channels or wells.
However, during a fracturing operation, major problems, such as screen-outs, can occur. Screen-outs happen when a continued injection of fluid into the fracture requires pressure beyond the safe limitations of the wellbore and surface equipment. This condition takes place due to high fluid leakage, excessive concentration of proppants, and an insufficient pad size that blocks the flow of proppants. As a result, pressure rapidly builds up. Screen-out can disrupt a fracturing operation and require cleaning of the wellbore before resuming operations. A delay in one fracturing operation can cause disruption on the completion and production of subsequent fractures.
The consequences of screen-out can depend on the type of completion used in fracturing. One of the common completions used for horizontal well is open hole liner completion. This involves running the casing directly into the formation so that no casing or liner is placed across the production zone. This method for fracturing can be quick and inexpensive. Open hole liner completion can also include the use of a ball-actuated sliding sleeve system, commonly used for multistage fracturing. However, if screen-out occurs near the toe of a horizontal wellbore, the small openings of the ball seats can make it difficult to use a coiled tubing or a workover string to wash the proppants out. One initial solution can include opening the well and waiting for the fracturing fluid to flow back. However, if the flow back does not occur, the only solution left is to mill out the completion and apply a different completion scheme to the wellbore. As a result, the entire operation can cause delays and higher expenses.
Another known completion method is a plug-and-perforate system, which is closely similar to the open hole liner system. This method involves cementing the liner of the horizontal wellbore and is often performed at a given horizontal location near the toe of the well. The plug and perforate method involves the repetitive process of perforating multiple clusters in different treatment intervals, pulling them out of a hole, pumping a high rate stimulation treatment, and setting a plug to isolate the interval, until all intervals are stimulated. The consequences of screen-out in this method may not be as severe compared to the ball-actuated sliding sleeve system, since the well can be accessed with coiled tubing to wash the proppants out.
Yet, another method used has included cemented liner completions with restricted entry. Cemented liner completions with restricted entry involve controlling fluid entry into a wellbore. This method provides a cemented liner or casing comprising a cluster of limited openings that can allow fluid communication between a region of a wellbore and the formation. However, a poor connection between the well and the formation often results in screen-out. Thus, screen out encountered in each completion method adds costs and causes disruption in fracturing operations and production.
As such, it would be useful to have an improved system and method for detecting screen-out using a fracturing valve for mitigation.